While Witch is largely a Minion class it's actual scope is so much larger, and nowhere is this more obvious than with the Ascendancies.
The two Witch Ascendancies at launch will be the Infernalist and Blood Mage.
Infernalist
The Infernalist is a Demon focused specialization that has the ability to summon Hellhounds as well as turn into a Demon. The Demon form is particularly wild, having incredible mobility thanks to the dash and has very high damage thanks to increased cast speed. The downside of the Demon Form is that it drains an increasing amount of life overtime, until you cannot sustain it anymore.
Blood Mage
The Blood Mage sounds interesting but unfortunately we were unable to playtest it. This Ascendancy will definitely buff Necromancer’s plethora of Bone Skills, and will likely also buff their Skeletal minions. The blood component uses life as a resource, making your skills cost life on top of mana. In exchange, you have a plethora of ways to buff yourself through life mechanics.